Indeed, hooks does not require RESPONSE interface,
and should be setup before, at the system level (i.e CMS_API)
Added exportation solution via CMS_HOOK_EXPORT.
Updated blocks settings for demo example project.
Added CMS_HOOK_RESPONSE_ALTER to give a last chance to alter the response before rendering.
This hook should not be used, when there are other alternative hook that answer the need, but this is proposed for now, as a way to alter response by adding css, js url, ...
Moved blog under official modules folder.
Cleaned theme of demo example project.
Renamed NODE_MODULE as CMS_NODE_MODULE.
